The subject matter disclosed herein relates to the field of seals used in turbomachinery. More particularly, the subject matter disclosed herein relates to a method and apparatus for dampening vibration of a compliant plate seal for application at the interface of a rotating component, such as a rotor in a turbine or compressor, and a stationary component, such as a casing or stator.
Dynamic sealing between the rotating component and the stationary component is an important concern in turbomachinery. Several methods of sealing have been used. In particular, sealing based on flexible members has been used that includes seal members, such as compliant plate seals and/or brush seals. Brush seals typically include tightly-packed, generally cylindrical bristles that are arranged in a staggered arrangement to reduce leakage. The bristles have a low radial stiffness that allows them to move in the event of a rotor excursion, while maintaining a tight clearance during steady state operations. Brush seals, however, are generally effective only below a limited pressure differential across the seal. Because of the generally cylindrical geometry of the bristles, the brush seals tend to have a low stiffness in the axial direction, which limits the maximum operable pressure differential in known brush seals.
In contrast, at least some known compliant plate seals have a plate-like geometry that has a significantly higher axial stiffness for a comparable radial stiffness and therefore, such seals have the capability of being used with larger pressure differentials than known brush seals. However, compliant plate seals may experience axial leakage between adjacent compliant plates, which may cause flow-induced vibrations or flutter of the compliant plates. Such vibration may reduce the lifespan of the compliant plates.